Rigify and WGT bones
Select them by name in Object Mode Menu:Select / Select pattern,
Type WGT*   
Delete the selected objects with X. 
Open a text region and paste this script and press the run script button:


import bpy

scene = bpy.context.scene
for o in bpy.data.objects:
    print(o.name)
    if o.name.startswith('WGT'):
        o.select = True
        scene.objects.unlink(o)